Flow cytometry is an outstanding research tool to research molecular and cellular biology. This fluorescence-based technology allows single-cell analysis of a high number of parameters to detect gene and protein expression. A highly valuable aspect of flow cytometry is the ability to sort for multiple specific cell populations, which is a critical step in modern day next generation RNA sequencing experiments and single cell gene expression analyses. The San Francisco VA Flow Cytometry Core Facility supports VA funded research and the VA research community. Multiple departments, including Rheumatology, Pathology, Neurosurgery, Urology, Cardiology and Pulmonology, require the flow cytometry services at this core facility and cell sorting is an integral part of several research projects. For the past 14 years to the present, the most valuable and main component of the core facility is a cell sorting flow cytometer, the Bectin Dickinson (BD) Biosciences FACS Aria IIu. The current cell sorter was manufactured in 2004, and unfortunately, in 2020 it will no longer be supported by the manufacturer; they will discontinue supplying parts and no longer offer service options which is required to maintain our aged equipment. There is a dire need for replacing the core facility?s cell sorter. The replacement equipment requested is an upgraded and advanced version of the current equipment, and it is called the BD Biosciences FACS Aria Fusion, which we will call the Aria Fusion. We expect the migration to the Aria Fusion to be a smooth transition with minimal additional training for management and for users as it utilizes identical software and fluidics mechanisms as the current Aria IIu. The Aria Fusion offers many technological and safety advancements over our current set up that will enhance VA research and increase the number of users. There are four main advancements of the requested flow cytometer: 1) The addition of the yellow-green laser (to replace our current near UV laser) will immensely improve the selection, detection, and the sensitivity of a vast number of current and newly developed fluors. This includes the ability to detect mCherry and tdTomato, popular fluors used in reporter mice. 2) The addition of a manufacturer-designed biosafety cabinet to encase the replacement cytometer will reduce the risk of exposure to infectious agents derived from BSL2 or higher risk group samples that become airborne during sorting. The core?s standard operating procedures (SOP) will be able to meet new international standards of biosafety for cytometry-based cell sorting. This will also expand the number of users to attract research on infectious diseases and clinically-derived samples. 3) The replacement Aria Fusion will have a high-powered blue laser coupled with a small particle detector. This special equipment is required for analyzing microvesicles, such as exosomes. Exosome research is a major interest for many San Francisco VA-funded Principal Investigators, and the new capability will attract new users and expand the research of current users. 4) The Aria Fusion will allow cell sorting into 96 well and 384 well plates. This new feature will facilitate research requiring the precision of single cell gene expression analyses. We are excited to request the Aria Fusion, a state of the art cell sorter that will become the foundation of the core facility and attract new users. Usage fees from all users will be sufficient for maintenance. This replacement is much needed; the current Aria will not be supported in 2020 and it lacks current day safety standards. The Aria Fusion advancements will expand the number of users. We expect the Aria Fusion to provide services critical towards accomplishing VA?s research goals towards understanding and treating diseases of high importance in the Veteran population.